Digital Signal Processing | Coursera

1.2.a Discrete-time signals

Discrete-time signals

  • Discrete-time signal:= A sequence of complex numbers
  • Dimension = 1 (for now)
  • Notation: x[n] where n is an integer
  • Two-sided sequences: x: \mathbb{Z} \rightarrow \mathbb{C}
  • n is one-dimensional “time”.
  • Analysis: Periodic measurement approach
    • Discrete-time signals can be created by an analysis process where we take periodic measurements of a physical phenomenon.
  • Synthesis: Stream of generated samples

Delta signal

Every sample is equal to 0 except for one sample equal to 1 if n is 0. The sound of the movie clapper is used to find the start time of a scene.

  • x[n]=1 if n=0
  • x[n]=0 if n \neq 0

Unit step signal

  • x[n]=0 if n<0
  • x[n]=1 if n \geq 0

Exponential decay

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